Make sure your design is within the specifications of the PCB service you use. Most hobbyist-friendly PCB services provide an Eagle design rule check file that can highlight anything that can't be reliably produced.

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Before sending your files to be manufactured you have make sure your design is within the specifications of the PCB service you will be using. To help you with this, the associated PCB service provides Design Rule Check files for Eagle. Grab a design rule file from your prefered PCB maker:

Eagle processes the DRC file and evaluates the board automatically. To run a design rule check:

#Open your PCB layout in Eagle

#Open your PCB layout in Eagle

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#Go to Tools > DRC... A DRC window will open from which you can load the manufacturers .dru file you previously downloaded. From this window you can also make adjustment to the various design specifications like minimum trace width (Sizes > Minimum Width), and trace clearance (Clearance). It is usually a good idea to increase these two settings a few mils if your board doesn't require absolute minimum the board house can produce.

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#Go to ''Tools > DRC...''

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#Once you've set it up just click (Check).

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#A DRC window will open. Load the manufacturer's DRC file.

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#Click ok to start the check

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From the DRC window you can adjustment the various design specifications like minimum trace width, clearance, etc. If a board doesn't need the smallest stuff the factory can make, we increase these settings a few mils as a safety margin.

[[image:Eagle-DRC2.jpg|600px]]

[[image:Eagle-DRC2.jpg|600px]]

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The DRC will scan your board and log all the errors on your board that go outside the scope of the specifications. By clicking on various log entries the portion of the board where they occur will be zoomed in, and the error in question highlighted. You go through them one by one. Once you've fixed all the errors you simply re-run the DRC again and check if everything is alright.

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The DRC will scan your board and log all the areas that go outside the manufacturer's limits. Click on various log entries to highlight each problem on the PCB.

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After fixing the errors, run the DRC again to see if everything passes. Rinse and repeat until the board passes the DRC.

Revision as of 14:29, 14 February 2012

Contents

Overview

In the last few years many inexpensive PCB services have popped up. It used to be that buying PCBs in hobby quantities was expensive and filled with gotchas.

Now, places like Seeed Studio can send your PCBs to the inexpensive prototyping factory in Shenzhen China, and ship them anywhere in the world at great prices. You get two-sided PCBs, with the works, starting at $1 per 5x5cm PCB. Turnaround is a few days, worldwide shipping starts at $3. It's a happy day for electronics hobbyists.

Others services like DorkBotPBX and BatchPCB pool multiple orders so the group benefits from bulk pricing. Enough people are using these services that turnaround is quite fast. DorkBotPBX offers signature purple PCBs that have become quite popular.

Our goal is to help you get your Eagle PCB designs manufactured. We show our 'pre-flight' checks to help spot problems before ordering boards. See examples of errors like under etching, over etching, and misaligned vias.

Check for air wires

It's easy to miss a small break in a trace, and Eagle doesn't provide any flashing warning signs. The zoom-unrouted ULP script will zoom in on any broken traces and save you headaches later.

Design rule check

Make sure your design is within the specifications of the PCB service you use. Most hobbyist-friendly PCB services provide an Eagle design rule check file that can highlight anything that can't be reliably produced.

Eagle processes the DRC file and evaluates the board automatically. To run a design rule check:

Open your PCB layout in Eagle

Go to Tools > DRC...

A DRC window will open. Load the manufacturer's DRC file.

Click ok to start the check

From the DRC window you can adjustment the various design specifications like minimum trace width, clearance, etc. If a board doesn't need the smallest stuff the factory can make, we increase these settings a few mils as a safety margin.

The DRC will scan your board and log all the areas that go outside the manufacturer's limits. Click on various log entries to highlight each problem on the PCB.

After fixing the errors, run the DRC again to see if everything passes. Rinse and repeat until the board passes the DRC.

Generate gerbers

Once you are sure your board is electrically sound, and that it falls within the manufacturing specifications of your PCB service you need to generate files that the manufacturer can use for production. These files are called Gerbers. To generate them PCB manufacturers provide a .CAM file.

Another pop up screen will show up, here you need to select the "Leading zero suppression" radio button, and select "2 4", and then click OK.

You should get a similar image to the one below. From there you can scroll through the layers in the lower left corner drop down menu.

Look for any errors in the board you can spot. More common ones are:

Problems with the footprint, the solder pad is sometimes buried by mask.

Drills outside board or flipped.

CAM didn’t export expected silkscreen layers.

Evaluating not only whether a silkscreen is present, but if it’s legable (size, location, etc).

Quickly seeing whether all of the vias on a board are tented or not.

One last doublecheck to make sure soldermask is on the correct side for the correct component (PCB’s that have components on both sides).

Zip up the files

Put it in an archive. We include a readme.txt with some basic information about the boards, here is an example.

"Name, email, service , PCB color, gerber format(2.4 leading)"

For Seeed Studio, Itead order the PCB online and email the files. BatchPCB has a web interface, while for DorkBotPCX you need to send them an email as described by their instructions.

Get your boards

In our experience, services take about this long from order to your hands:

Seeed Studio, from 2 to 4 weeks

ITead Studio, from 2 to 4 weeks

DorkBotPBX, around 2 weeks

BatchPCB, from 2 to 4 weeks

Seeed and ITead offer cheaper boards if you only test 50% of them. The tested boards will be wrapped in masking tape and/or marked on the side with a marker.

Inspection

Before you build the first PCB, spend five minutes looking it over. E-tested PCBs will nearly always be good. If a PCB is untested then you absolutely must inspect the board, or risk a broken or shorted trace under a chip that you'll never be able to find.

Here are three common problems that can cause hours and days of debugging headaches.